"Factory-scale farms don't just house hundreds of genetically similar
animals in tight quarters over vast cesspools collecting their waste.
They also house a variety of bacteria that live within those unfortunate
beasts' guts. And when you dose the animals daily with small amounts of
antibiotics—a common practice—the bacteria strains in these vast germ
reservoirs quite naturally develop the ability to withstand
anti-bacterial treatments." Tom Philpott
